Detection and communication of plunger position using induction

ABSTRACT

A syringe system, including a plunger, a microcontroller, a battery, and a coil. The syringe barrel having a proximal end, a distal end, and a cylindrical sidewall defining a longitudinal axis, the cylindrical sidewall extending longitudinally between the proximal and distal ends, the sidewall having an exterior surface and defining an internal volume, the plunger being positioned between the proximal and distal ends of the syringe barrel and being movable within the internal volume with respect to the syringe barrel in the longitudinal direction. The syringe barrel further includes a label disposed on the sidewall and having at least two conductive strips extending in a non-parallel direction with respect to the longitudinal axis and having unique lengths. The microcontroller is configured to determine a position of the plunger with respect to the syringe barrel by measuring a current induced in the coil by the at least two conductive strips.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 16/615,948filed on Nov. 22, 2019, which is a section 371 of InternationalApplication No. PCT/US2018/034605, filed May 25, 2018, which waspublished on Nov. 29, 2018 under International Publication No. WO2018/218128 A1, and which claims priority to U.S. Provisional PatentApplication No. 62/511,086, filed May 25, 2017, the entire contents ofeach of which are incorporated herein by reference.

BACKGROUND

It has been observed in a fast-growing healthcare system that patientadherence to drug programs impacts the cost to stakeholders. The effortto confirm adherence in low cost devices, such as prefilled syringes,has lagged more than other complex delivery systems in terms ofconnectivity. This is primarily due to the cost of the communicationtools, many of which may cost more than the product itself.

One problem sometimes exhibited by prefilled syringes is the unwantedmovement of their plungers during transit. Internal/externaldifferential pressure changes due to, for example, changes intemperature or atmospheric pressure, may cause the plunger to moveduring air shipment and/or travel through different elevations. Themovement of the plunger can affect product sterility. Another problem isthe invasiveness of other potential solutions. Low cost injectiondevices, like prefilled syringes, have extremely strict manufacturingstandards regarding modifications to the size, shape, and materials ofthe barrel and syringe plunger.

BRIEF SUMMARY

In an exemplary embodiment of the present disclosure, a syringe systemis disclosed. The syringe system having a plunger including amicrocontroller, a battery, and a coil connected to the microcontrollerand the battery by two or more electrical leads. A syringe barrel has aproximal end, a distal end, and a cylindrical sidewall defining alongitudinal axis, the cylindrical sidewall extending longitudinallybetween the proximal and distal ends. The sidewall has an exteriorsurface and defines an internal volume. The plunger is positionedbetween the proximal and distal ends of the syringe barrel and ismovable within the internal volume with respect to the syringe barrel inthe longitudinal direction. The syringe barrel further includes a labeldisposed on the sidewall and formed by at least two conductive stripsextending in a non-parallel direction with respect to the longitudinalaxis and having unique lengths. The microcontroller is configured todetermine a position of the plunger with respect to the syringe barrelby measuring a current induced in the coil by the at least twoconductive strips.

In some embodiments of the system, the plunger includes a head section,at least a portion of which extends outside of the syringe barrel, andthe battery and the microcontroller are disposed in the head section.

In some embodiments, the system further includes a temperature sensorconfigured to output a signal representative of a temperature of thesyringe system to the microcontroller. In some embodiments, the systemfurther includes a wireless communication interface.

The microcontroller is configured to transmit the temperature datareceived from the temperature sensor to a smart device via the wirelesscommunication interface.

In some embodiments, the system further includes a wirelesscommunication interface. The microcontroller is configured to transmitplunger position data to an external device via the wirelesscommunication interface.

In some embodiments, the external device is configured to provide analert to a user if the plunger position is determined by themicrocontroller to have moved in excess of a predetermined distance.

In some embodiments, the microcontroller is configured to periodicallycause the battery to supply the current to the coil at predeterminedintervals.

In some embodiments, the at least two conductive strips are transparent.

In some embodiments, the at least two conductive strips are arranged onthe sidewall of the barrel so as to be spaced apart from one another inthe longitudinal direction, and are arranged in order according tocircumferential length.

In another exemplary embodiment of the present disclosure, a method ofusing a syringe system is disclosed. The system including a plungerhaving a microcontroller, a battery, and a coil connected to themicrocontroller and battery by two or more electrical leads. The syringesystem further includes a syringe barrel defining a longitudinal axisand receiving the plunger, and a label disposed on a sidewall of thesyringe barrel and having at least two conductive strips extending in anon-parallel direction with respect to the longitudinal axis and havingunique lengths. The method includes generating, by the microcontroller,an eddy current in the coil by causing the battery to supply a currentto the coil via the two or more electrical leads. An amplitude of thegenerated eddy current depends on a relative position of the coil withrespect to each of the conductive strips of the label along alongitudinal direction of the syringe barrel. The method furtherincludes measuring, by the microcontroller, the generated eddy currentin the coil via the two or more electrical leads, and determining, bythe microcontroller based on the measured eddy current, a position ofthe plunger with respect to the syringe barrel.

In some embodiments, the method can further include transmitting, by themicrocontroller via a wireless communication interface, data regardingthe determined plunger position to an external device.

In some embodiments, the method can further include generating, by theexternal device, one or more alerts based on data regarding the plungerposition.

In some embodiments, the method can further include generating, by atemperature sensor, temperature data based on a measured temperature ofthe syringe system; and transmitting, by the microcontroller via awireless communication interface, the temperature data to an externaldevice.

In some embodiments, the method can further include generating, by theexternal device, one or more alerts based on the temperature data.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosure will now be described in connectionwith the attached drawings. For the purpose of illustration, there areshown in the drawings embodiments which are presently preferred. Itshould be understood, however, that the invention is not limited to theprecise arrangements and instrumentalities shown.

FIG. 1 is a block diagram depicting features of the syringe system, inaccordance with a preferred embodiment of the present invention;

FIG. 2 is a perspective view of a plunger for a syringe system, inaccordance with a preferred embodiment of the present invention;

FIG. 3 is a perspective view of a syringe barrel for a syringe system,in accordance with a preferred embodiment of the present invention; and

FIG. 4 is a perspective view of the plunger of FIG. 2 and the syringebarrel of FIG. 3 assembled together as part of a syringe system, inaccordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION

Certain terminology is used in the following description for convenienceonly and is not limiting. The words “right,” “left,” “lower,” and“upper” designate directions in the drawings to which reference is made.The words “inwardly” and “outwardly” refer to directions toward and awayfrom, respectively, the geometric center of the apparatus and designatedparts thereof. The terminology includes the above-listed words,derivatives thereof, and words of similar import. Additionally, thewords “a” and “an,” as used in the claims and in the correspondingportions of the specification, mean “at least one.”

The present disclosure may provide an affordable, scalable method ofelectrical communication to a drug delivery device, such as a single usesyringe system 100, through the use of electrical induction. FIG. 1 is ablock diagram depicting features of the syringe system, in accordancewith aspects described herein. The syringe system 100 preferablyincludes at least a plunger 101 and a syringe barrel 102. The plunger101 may be manually or automatically operated to apply pressure withinthe syringe barrel 102 such that a medicament (not shown) within thesyringe barrel 102 can be dispensed through an opening, such as a needle301. The syringe system 100 preferably allows for communication ofstatus information (e.g., completion of an injection, movement of theplunger 101, temperature information, and the like) to an externaldevice 103, such as a smart device, which may include a smart phone,tablet, personal computer, or other digital medical system or the like,through Bluetooth Low Energy or other wireless protocols via a wirelesscommunication interface 104. Information regarding the position of theplunger 101 is preferably generated using electrical induction generatedin a conductive coil 108 wrapped around or within the plunger 101, inconjunction with a microcontroller 105, which, in certain aspects, maybe a Cypress PSoC 6 32-bit internet-of-things microcontroller or thelike, and which is preferably embedded within the plunger 101.

The syringe barrel 102 preferably includes a label 106 formed thereon oraffixed thereto, preferably on an outer surface of the syringe barrel102. The label 106 may be placed on the outer circumference or an innercircumference of the syringe barrel 106, although the label 106 may alsobe embedded within a material of the syringe barrel 102. The label 106preferably includes varying amounts of a conductive substrate runningalong a length of the label 106 in a longitudinal direction of thesyringe barrel 102. In a preferred embodiment, the label 106 preferablyincludes a plurality of conductive strips 303 (FIG. 3 ), each of whichextends in a circumferential direction, which may include a non-paralleldirection with respect to a longitudinal axis of the syringe barrel 102,on the sidewall 304 of the syringe barrel 102. At least two of theconductive strips 303 have unique lengths, and preferably, each of theconductive strips 303 has a unique length. In another embodiment notshown, the conductive strips 303 may be oriented at an angle. Each ofthe conductive strips may be oriented at the same angle or at differentangles. In these embodiments, each of the conductive strips 303 may havea unique effective length, which is the transverse length of theconductive strip 303 (i.e., the cosine of the pitch angle with respectto the longitudinal axis multiplied by the overall length of theconductive strip 303). Thus, conductive strips having the same overalllength could be arranged at different angles to provide an array ofstrips each having a unique effective length. In the embodiment shown inFIG. 3 , the overall length for each strip is the same as the uniqueeffective length thereof consequently, as used herein, the term “uniquelength” will also refer to the unique effective length. The conductivestrips 303 are preferably spaced apart from one another in thelongitudinal direction on the syringe barrel 102 and may be arranged inorder according to circumferential length (e.g., the longest strip maybe adjacent one end of the syringe barrel 102 while the shortest stripcan be adjacent to the other end). The conductive strips 303 may becomposed of materials including, but not limited to, carbon, silver,copper ink, or the like. In certain aspects, one or more of theconductive strips 303 may be printed using a transparent conductivematerial. In other embodiments, each of the conductive strips may becomprised of a wire.

In other aspects, the label 106 may also be placed on other elementsnearby, such as in the case of a syringe accessory, auto injector, orwearable drug delivery device (not shown), if it is in close enoughproximity to the conductive coil 108 located on the plunger 101 toinduce eddy currents therein. As described in further detail below,depending on a location of the plunger 101 with respect to the syringebarrel 102, and more particularly, a location of the coil 108 withrespect to the label 106, the microcontroller 105 preferably measures adifferent eddy current produced by electrical induction generated in thecoil 108 of the plunger 101 in part by a combined transverse length ofthe conductive strips 303 present at the particular location of thelabel 106.

The detected position is preferably written to a memory 107 in theplunger 101 to record, for example, any unintentional movement of theplunger 101 during transport. The memory 107 is preferably powerless,but can also be powered by a battery 202 (FIG. 2 ) or other powersource. The microcontroller 105 may also use an embedded temperaturesensor 109 to detect the temperature of the plunger 101, and may alsowrite this temperature data to the memory 107 at a predetermined timeinterval, which may allow a temperature history of the syringe system100 to be tracked to ensure proper cold chain integrity. In certainaspects, the syringe system 100 may alert the user, for example via theexternal device 103, of deviations from proper storage temperatureconditions. This feature may also be used to notify a user that themedicament is at the proper temperature for injection after it has beenremoved from cold chain storage. Additionally, the detection of theplunger 101 positions may allow a user to see when and how much of adose was administered to help ensure adherence and proper drug dosing.

The use of a microcontroller 105 and induction sensor 110 in accordancewith aspects of the present invention may help reduce the cost of aplunger tracking system compared to some other potential solutions byeliminating the number of components needed, and may also allow for thetracking of the movement of the plunger 101 during transport. Forexample, the low energy microcontroller 105 may determine if there hasbeen a change in position of the plunger 101 by sampling atpredetermined intervals. In certain embodiments, the interval may be onesecond or shorter. If a change in the position of the plunger 101 isdetected, the microcontroller 105 may start to record data and transmitto the connected smart device 103 via the wireless communicationinterface 104. The smart device 103 may alert the user that a change inthe position of the plunger 101 has been detected.

The syringe system 100 may also be able to track and record thetemperature thereof, and the length of time since the syringe barrel 102was filled, by using an internal clock (not shown) of themicrocontroller 105, as well as the on-board temperature sensor 109,which may be used to measure the temperature at a pre-set interval. Themicrocontroller 105 may write the temperature data to the memory 107during an ‘active’ duty cycle of the microcontroller 105.

In certain aspects, the electronics used in this disclosure may below-cost and small enough in scale to use on prefilled syringes andother injection devices. It may also be scaled to fit larger devices.The microcontroller 105 may have considerable power savings overpreviously created systems through the use of ultra-low boot cycles anda considerable ‘inactive’ duty cycle, which may minimize power drain andidle time.

FIG. 2 is a perspective view of the plunger 101 for use in an embodimentof the syringe system 100. The plunger 101 may use the battery 202 (suchas a CR1220) to provide power to the coil 108, the microcontroller 105,and/or other components thereof. In certain aspects, the battery 202 maybe rechargeable. The plunger 101 may house the battery 202 within a headsection 201 at one end of the plunger 101. The head section 201 may alsocontain the microcontroller 105 (not shown in FIG. 2 ), which may bemounted to a printed circuit board 203. A set of two or more electricalleads 204 preferably runs from the microcontroller 105 in the headsection 201 through a shaft 205 of the plunger 101, to where the leads204 connect and transmit electrical signals to and from the coil 108 ata distal end of the plunger 101 opposite to the head section 201. Thebattery 203 and microcontroller 105 may be located on top of the syringeplunger 101 with the electrical leads 204 running from themicrocontroller 105 to the piston 206, which may contain a lockingmechanism (not shown) for a medicament delivery system.

In a preferred embodiment, the battery 203 periodically supplies currentto the coil 108 through the electrical leads 204. By supplying currentto the coil 108, an electrical induction field is generated at the coil108 that can interact with the conductive strips 303 (FIG. 3 ) presenton the label 106 disposed on the syringe barrel 102, which can be usedto induce one or more eddy currents in the coil 108. The amplitude ofthe eddy current induced in the coil 108 depends at least in part on arelative position of the coil 108 with respect to each of the conductivestrips 303 in the label 106 along the longitudinal direction of thesyringe barrel 102 at the time the battery 203 supplies the current. Theeddy current is influenced by one or more of the conductive strips 303that are closest to the coil 108 when the current is applied, and theunique lengths of the conductive strips 303 distinguish the magnitude ofthe eddy current depending on the relative location of the coil 108. Themicrocontroller 105 measures the induced eddy current via the electricalleads 204, and interprets and converts the measurement into datarepresenting a position of the plunger. In some embodiments, themicrocontroller 105 is configured to periodically cause the battery 203to supply current to the coil 108 at predetermined intervals. Forexample, the battery 203 may supply current every second, every fiveseconds, every minute, or any other interval. The microcontroller 105may, in such embodiments, also determine the plunger position at thesesame supplying intervals.

FIG. 3 illustrates a syringe barrel 102 for a syringe system 100, inaccordance with aspects disclosed herein. In certain embodiments, thesyringe barrel 102 may have the label 106 with one or more conductivestrips 303 of varying size arrayed in a smallest-to-largest orlargest-to-smallest configuration. In certain aspects, the smallerconductive strips 303 provide a smaller inductive force on the coil,while the larger conductive strips 303 may provide a larger inductiveforce on the coil. The configuration of metal printing of the label 106may be in several forms, with the configuration shown in FIG. 2 shown asonly one exemplary aspect of the configuration.

The syringe barrel 102 has a proximal end and a distal end and acylindrical sidewall 304 extending longitudinally therebetween. Thesidewall 304 has an exterior surface and defines an internal volumewithin which medicament may be stored. A barrel opening 302 ispreferably located at the proximal end of the syringe barrel 102 and maybe configured to accept medicament containers, such as drug ampules orvials. The plunger 101 may also preferably be inserted into the barrelopening 302 during manufacture and for transport, with the plunger 101being movable within the internal volume of the syringe barrel 102 withrespect thereto in the longitudinal direction for dispensing medicament.The medicament may be dispensed through a needle 301 or other deliverymechanism at the distal end of the syringe barrel 102.

FIG. 4 illustrates an assembled syringe system 100, in accordance withaspects described herein. The plunger 101 is shown inserted into thesyringe barrel 102 such that the coil 108 interacts with the label 106.Eddy currents generated in the coil 108 are communicated over theelectrical leads 204 to be processed by the microcontroller 105 (notshown in FIG. 4 ) housed on the circuit board 203 and located in thehead portion 201 of the plunger 101. In certain aspects, a safety cover401 may be used to cover the needle 301 or drug delivery mechanismduring transport and before use.

The syringe system 100 preferably allows healthcare providers toautomatically monitor the state of the low-cost injection device, whichenables them to track dosing regimen adherence, shelf-life evaluation,plunger movement during transportation, and cold chain integrity.

The technology may also be implemented into more complex injectiondevices that already include wireless connectivity. Autoinjectors whichutilizes a moving plunger 101 and a syringe barrel 102 may incorporatefeatures of the disclosure described herein. The syringe barrel 102 maybe made of materials that do not interfere with the magnetic fieldcreated by the coil, such as polymers, ceramics, and some metals.On-body or wearable injectors could also accommodate the technologydescribed herein. In addition, this technology may be particularlyrelevant for syringes that utilize a safety system.

Further, the syringe system 100 may also be used in a hospitalenvironment to communicate automatically with the hospital inventorymanagement system, such that the syringe use may be tracked in real-timeand re-ordered automatically based on a pre-set inventory level.

The syringe system 100 may be produced by over-molding or insert-moldingthe microcontroller 105, battery 102, and electrical conductors into theplunger 101, as described throughout this disclosure. This may be doneduring a general injection molding process.

The label 106 may be applied to the syringe barrel 102 using anyconventional syringe labeling equipment. The piston 206 may also containelements of the electrical system, such as the coil 108, so that whenthe plunger 101 is assembled to the piston 108, it may complete theelectrical circuit. In some aspects, some of the electrical componentsmay be contained within a syringe flange adaptor (not shown), or in thesurrounding components of an autoinjector or wearable on-body drugdelivery system.

Embodiments of the present invention may also be used in a similarfashion with existing self-injection devices, like a prefilled syringe.The movement of the plunger 101 and/or temperature of the device may bedetected by the microcontroller 105. The microcontroller 105 may readand record the information, then may transmit the information to a smartdevice 103 via, for example, BLE communication. The external device 103may have a connected application to read, record, and display theinformation from the syringe system 100. This information may also berelayed to healthcare providers and other stakeholders.

These aspects are not meant to be limiting. For different injectorsystems, the positioning and size of the circuit may vary. It will beappreciated by persons skilled in the art that the present disclosure isnot limited by what has been particularly shown and describedhereinabove. Rather the scope of the present disclosure includes bothcombinations and sub-combinations of various features describedhereinabove as well as modifications and variations which would occur topersons skilled in the art upon reading the foregoing description andwhich are not in the prior art.

What is claimed is:
 1. A syringe system, comprising: a plungercomprising: a microcontroller, a battery configured to power themicrocontroller, and a coil connected to the microcontroller and thebattery; a syringe barrel having a proximal end and a distal end anddefining a longitudinal axis between the proximal end and the distalend, the syringe barrel comprising a cylindrical sidewall that extendslongitudinally between the proximal end and the distal end, thecylindrical sidewall defining an internal volume, and the plunger beingconfigured to move longitudinally within the internal volume withrespect to the syringe barrel; and one or more conductive stripsextending in a non-parallel direction with respect to the longitudinalaxis, wherein the microcontroller is configured to determine a positionof the plunger with respect to the one or more conductive strips basedon an inductance of the coil.
 2. The system of claim 1, wherein each ofthe one or more conductive strips defines a ring extendingcircumferentially about the longitudinal axis.
 3. The system of claim 2,wherein the ring is on the cylindrical sidewall of the syringe barrel.4. The system of claim 1, wherein the plunger further comprises awireless communication interface connected to the microcontroller, thewireless communication interface being configured to transmit theposition of the plunger to an external device.
 5. The system of claim 4,wherein the wireless communication interface is configured to transmitthe position of the plunger via the Bluetooth standard.
 6. The system ofclaim 5, wherein the Bluetooth standard is the Bluetooth Low Energystandard.
 7. The system of claim 4, wherein the external device isconfigured to provide an alert if the position of the plunger isdetermined to have moved relative to a prior position of the plunger inexcess of a predetermined distance.
 8. The system of claim 1, wherein:the plunger further comprises a memory connected to the microcontrollerand the battery, and the position of the plunger is written to thememory.
 9. The system of claim 8, wherein the battery is configured topower the memory.
 10. The system of claim 1, wherein the microcontrolleris configured to cause the battery to supply current to the coil atpredetermined intervals.
 11. The system of claim 1, wherein a medicamentis contained in the internal volume of the syringe barrel, the systemfurther comprising: a needle, wherein the plunger is configured to applypressure within the internal volume so that the medicament is dispensedthrough the needle.
 12. The system of claim 1, wherein the plungerfurther comprises a printed circuit board (PCB), and the microcontrolleris mounted to the PCB.
 13. The system of claim 1, further comprising: apiston attached to the plunger.
 14. The system of claim 1, wherein theone or more conductive strips are on an outer surface of the cylindricalsidewall of the syringe barrel.
 15. The system of claim 1, wherein theone or more conductive strips are on an inner surface of the cylindricalsidewall of the syringe barrel.
 16. The system of claim 1, wherein theone or more conductive strips comprise conductive ink.
 17. The system ofclaim 16, wherein the conductive ink comprises at least one of carbon,silver, or copper.
 18. The system of claim 1, wherein the one or moreconductive strips comprise a wire.
 19. The system of claim 1, whereinthe one or more conductive strips are transparent.
 20. The system ofclaim 1, wherein each of the one or more conductive strips has adifferent length.